# Structure Determination of G Protein-Coupled Receptors by Microcrystal Electron Diffraction

> **NIH NIH R01** · ARIZONA STATE UNIVERSITY-TEMPE CAMPUS · 2020 · $297,999

## Abstract

SUMMARY
The overall aim of this project is to use the recently developed cryo-electron microscopy technique of
microcrystal electron diffraction (MicroED) for the structure determination of G protein-coupled
receptors (GPCR). GPCRs are an extremely important class of membrane proteins and are responsible
for controlling a wide variety of physiological responses. Because of their key physiological roles, a
large percentage of currently approved drugs target these receptors, and they represent attractive
targets for drug development. Despite the importance of GPCRs, detailed understanding of their high
resolution structure and function is limited in large part because of the difficulty associated growing
large crystals necessary for X-ray crystallography. In this project, MicroED will be used to study GPCR
structure, as the method is capable of determining structures from microcrystals several orders of
magnitude smaller than those used by conventional X-ray crystallography. The project will employ and
optimize new MicroED sample preparation methodology to allow data collection from GPCR
microcrystals grown in the viscous lipidic cubic phase (LCP). Electron diffraction data will be collected
and processed using previously developed MicroED methods. The new methods for GPCRs will be
validated in Aim 1 using the previously solved beta-2 adrenergic receptor (β2AR) and A2A Adenosine
receptor (A2AAR) as models. New structural details will be studied in Aims 2 and 3 by using MicroED
to improve the resolution and modeling of the rhodopsin-arrestin complex (Aim 2), and finally to
determine a novel structure of the serotonin receptor 5HT4 (Aim 3). The long term goal of this project
is to develop and use MicroED as a high-throughput structure determination method for GPCRs and
other important membrane proteins grown in LCP. By determining the structures outlined in these aims,
not only will new light will be shed on GPCR structure and function, but the optimized protocols will
open the door to MicroED analysis for a variety of membrane protein samples. This will make MicroED
a valuable tool for membrane protein structure determination of targets that have resisted other
structural methods because of difficulties with optimizing crystal size for X-ray crystallography.

## Key facts

- **NIH application ID:** 9974533
- **Project number:** 5R01GM124152-04
- **Recipient organization:** ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
- **Principal Investigator:** Brent Nannenga
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $297,999
- **Award type:** 5
- **Project period:** 2017-09-30 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9974533

## Citation

> US National Institutes of Health, RePORTER application 9974533, Structure Determination of G Protein-Coupled Receptors by Microcrystal Electron Diffraction (5R01GM124152-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9974533. Licensed CC0.

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